1. Field of the Invention
The present invention relates to a method and apparatus for marking positions of defective portions on a long elongated body such as an electric wire, a pipe, or a hose, and a bundling apparatus for bundling a plurality of long bodies.
This application is based on patent application number Hei 11-163319 filed in Japan, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Long bodies, such as electric wires, various kinds of pipes, hoses of various kinds of materials, and rods or lines of steel, glass, plastic and the like, are being manufactured actively. At the site where such long bodies are manufactured, defective portions like scratches present on the surface of a manufactured long body are detected by a specific method. In a case of electric wires or the like, for example, an ultrasonic probing apparatus, a detecting apparatus using an excess current or the like, are used to detect scratches on the surface of such a wire.
When a defective portion is detected by such a method, the production line is stopped to check the defective portion or the position thereof is automatically recorded in a computer. Mere recording of a defective portion in a computer without marking it on a product itself makes it hard to find the defective portion in such a case where the product is used after cutting out the defective portion.
Conventionally, therefore, some methods have been used to mark the position of a defective portion on a product itself. The conventional marking methods include a scheme of spraying ink on the surface of a product and a scheme of sticking a seal on a product.
The conventional marking methods however have the following shortcomings.
The scheme of spraying ink often sprays ink while a long body is running to be wound up, and faces such a problem that the ink gets thinner as the running speed becomes higher. If the actual inspection of a marked portion proves the determination of the defective portion wrong, the marking should be removed. In the case of sprayed ink, however, it is hard to remove the marking. Further, because only a specific portion on the outer surface of a long body is marked, it is difficult to spray ink all around the long body. In this case, it is not easy to find a marking made on a specific portion and the marking may be missed.
With regard to the scheme of attaching a seal, depending on the surface condition of the long body, it may be difficult to attach a seal on a long body. If an easily separable seal is used to facilitate the later removal of the seal, the seal may be separated at the time of transportation or the like, so that the position of the associated defective portion will not be located. Like in the case of the ink spraying method, it is difficult to put a marking all around a long body, thus making it hard to find the marked portion.
As a solution of the above problems, a scheme of making a mark by winding a ring-shaped elastic body like a rubber band on a long body is disclosed in Japanese Patent Application, First Publication No. Hei 9-202532. This publication discloses the structure which prepares a ring-like elastic body by securely joining both ends of a line-like elastic body of a given length and feeding it.
This structure, however, has the disadvantage of the structure for securely joining both ends of a line-like elastic body becoming large. In addition, the strength of the joined portion should be considered. In other words, if the elasticity of the ring-like elastic body is increased to enhance the winding strength, the secured portion may be cut. Further, to remove a marking, the ring-like elastic body should be cut with scissors or the like. When a long body is cut, the ring-like elastic body can be removed through the cut portion. But, in a case where the actual inspection of a marked portion proves the determination of the defective portion wrong or a long body cannot be cut due to some restriction in the production process, the ring-like elastic body still has to be cut with scissors or the like, which is troublesome.
Accordingly, it is a primary object of the present invention to provide a defective-portion marking method and defective-portion marking apparatus which can reliably put a mark on a long body even when the running speed of the long body becomes high, can easily remove the mark later when needed, can prevent separation of a mark at the time of transportation or the like, can put a mark all around a long body, thus facilitating later locating of the marked portion, and eliminate the need for securely joining both ends of a line-like elastic body.
It is another object of this invention to provide a bundling apparatus which makes untying the bundled long bodies easier.